LAFAYETTE, Louisiana — The longtime secretary to former Lafayette Parish District Attorney Mike Harson has been sentenced to 18 months in federal prison for her role in a yearslong bribery scheme that involved DWI offenders.

The Advocate reports (http://bit.ly/1Tqia8W) 61-year-old Barna D. Haynes, who pleaded guilty in 2013, was ordered Friday to report to the U.S. Bureau of Prisons on Aug. 20.

Haynes was a central figure in a federal investigation that resulted in guilty pleas from other members of the 15th District Attorney's Office and the DWI scheme leader, former private investigator Robert Williamson.

Harson was not identified as a target of the investigation, but federal prosecutors wrote in court filings that the scheme was carried out without Harson's knowledge because of a "lack of oversight and safeguards."